1. Field
The present disclosure relates to a semiconductor device having a dual parallel channel structure and a method of fabricating the same. More particularly, the present disclosure relates to a high power semiconductor device having a dual parallel channel structure capable of reducing an On-resistance and preventing a relatively large electric field from being applied to a gate oxide layer under a gate and a method of fabricating the same.
2. Description of the Related Art
In a power converting system for receiving a main power to be converted into a voltage required for a plurality of devices or to be distributed, the function of a power switching device is important. For example, the power switching device may be realized by a transistor based on a semiconductor material such as silicon, GaN, or SiC, like a metal oxide semiconductor field effect transistor (MOSFET). The power switching device is required to have a relatively high breakdown voltage. A large amount of research on the power switching device is being conducted in order to obtain characteristics of reduction in an On-resistance, high density integration, and rapid switching.
For example, a field effect transistor (FET) of a trench gate structure, in which a trench is vertically formed and a gate oxide layer and a gate are formed in the trench, is advantageous in terms of high current and high density integration. However, in the FET of the trench gate structure, since the gate oxide layer under the gate is exposed to a drain formed under a substrate, when a high voltage is applied to the drain in an Off state, a large electric field is concentrated on the gate oxide layer under the gate. Therefore, insulation breakdown may be generated by the gate oxide layer before reaching the breakdown voltage.
On the other hand, it is relatively difficult to put the MOSFET using SiC into commercial use due to the relatively low channel mobility. Therefore, for example, research on improving mobility through a nitridation process is being conducted. However, since a threshold voltage is lowered as the mobility is increased, there are limitations to improving the mobility.